Method of forming pressed sheet metal spoked wheels



J. M LENNAN METHOD OF FORMING PRESSED SHEET METAL SPOKED WHEELS Filed April 16, 1934 2 Sheets-Sheet 1 INVENTOR "65)! Nadia 777471 ATTORNEYS J. M LENNAN METHOD OF FORMING PRESSED SHEET METAL SPOKED WHEELS Filed April 16, 1934 2 Sheets-Sheet 2 m m V w h a. J

ATTORNEYS Patented Oct. 22, 1935 ATET OFFICE METHOD OF FORMING PRESSED SHEET METAL SPQKED WHEELS John MacLennan, Detroit, Mich.. assignor to v Kelsey-Hayes Wheel Company, Detroit, Mich.,

a corporation of Delaware Application April 16, 1934, Serial No. 720,871

Claims.

The invention relates to the manufacture of vehicle wheels of that type in which the wheel center is formed from pressed sheet metal and includes a series of hollow spokes with integral closed ends for engagement with and attachment to the wheel rim. It is one of the objects of the invention to form such a structure from a pressed sheet metal blank without localized over-drawing or over-stressing of any portion thereof, thereby avoiding the thinning and weakening of the metal which might otherwise result. It is a further object to obtain a process which facilitates the formation of a Wheel of predetermined design. With these objects in view the invention consists in the method as hereinafter set forth.

In the drawings:

Fig. l is a cross section through the wheel forming the product of my improved process;

Fig. 2 is a cross section through the original sheet metal blank;

Figs. 3, 4, 5, and 6 show the successive steps in cupping the central portion of the blank;

Fig. 7 is a plan view of the blank after the scalloping operation;

Fig. 8 is a cross section showing the bowlin operation;

Fig. 9 is a similar view showing the initial spoke forming operation;

Fig. 10 is a cross section on line l0l0, Fig. 9;

Fig. 11 is a view similar to Fig. 9 showing the reverse bowling operation;

Fig. 12 is a plan View illustrating the notching operation;

Fig. 13 is a cross section on line I3--l3, Fig. 12, showing the refashiom'ng of the spokes after the notching operation;

Figs. 14, 15, and 16 show the successive operations in forming the bolting-on flange;

Fig. 17 illustrates the spoke facing or trimming operation.

While my invention is applicable to various modified constructions of wheel, I shall describe its application to the manufacture of a wheel illustrated in Fig. 1 and which is of the following construction:

A is a central hub portion having a radially inwardly extending flange B at one end thereof provided with a series of apertures C for engagement with the bolts which demountably secure the wheel upon its hub. Extending from the opposite end of the portion A is a dished portion D which merges into a series of radially outwardly extending hollow spokes E. These spokes are of channel cross section open on the inner side of the wheel and each provided with an integral end flange G extending across a channel and forming a bearing for the rim H. The rim is secured to the spokes by rivets I which pass through the flange G and adjacent portion of the rim.

In forming a structure such as described from 5 pressed sheet metal there is considerable danger of overdrawing certain parts of the blank resulting in the thinning and weakening of the same and there'is also danger of over-stressing certain parts which may result in fracture. This is par- 1 ticuiarly true with reference to the formation of the spoke portions with their integral end flanges.

I have discovered that by a certain sequence of operations these spokes as well as all other porticn-s of the wheel can be successfully formed, avoiding localized over-drawing or over-stressing of the metal as follows: A circular sheet metal blank J has its central portion cupped by a series of successive drawing operations as indicated at J, J J J Figs. 2 to 6 inclusive. This results in 2 the forming of a cylindrical portion K having a I closed end K and outwardly extending annular flange K at the opposite end of the cylindrical portion which remains in the plane of the original blank. The peripheral edge of the flange K is then scalloped as indicated at K Fig. 7, the number of scallops corresponding to the number of spokes to be formed. The blank is next pressed between dies M and M, Fig. 8, to convert the flange K into an outwardly flaring bowl L. The bowl is then pressed between dies N, N, Fig. 9, to form a series of pockets L depressed in the portions thereof in radial alignment with the outward convolutions of the scallops. This will draw the metal of said scallops radially inward and will form thereof the outer end of the pocket which is deepest at this point and diminishes in depth in a radially inward direction to the point L where it merges into the bowl. There is also imparted to the bowl a corrugated cross section in a line parallel to the periphery as shown in Fig. 10. Following these operations the blank is again pressed between dies 0 O to reverse the bowl, swinging the pocketed portions through an angle and bringing the ends of said pockets parallel to the axis of the bowl, as shown in Fig. 11. The blank is then notched or cut away in the corrugations intermediate the pockets L as shown at P, Fig. 12, following which it is repressed to bend downward the portions P on 60 opposite sides of the notches P and to merge the same into spokes.

The end K of the central cupped portion of the blank is then pierced and fashioned to form a bolting-on flange for the wheel. These opera- 'reversely-forming the bowlthereby bringing said tions include, first, piercing to form a central aperture Q and bolt receiving apertures C as shown in Fig. 14, pressing to form a flange Q surrounding the aperture Q as shown in Fig. 15, and countersinking and flanging around the aperture C as indicated at C, Fig. 16. This completes the bolting-on flange which is strengthened by ribs K at distributed points therearoun'd and which may be pressed in the cylindrical portion K as'shown in Fig. 6.

If desired, the channel faces of the spokes may pressed inward from the convex side to form projections from the concave side thereof, and

projections on the convex side thereof.

7 2. In a method of forming pressed sheet metal spoked wheels, the steps of pressing a flat sheet 1 metalblanl: forming a flaring bowl with radially extending pockets projecting inward from the convex side forming projections from the concave side thereof, and re-pressing thereby reversing the bowl and bringing the projections on the convex side thereo-f.

3 In a method of forming pressed sheet metal i spoked wheels, the steps of pressing a flat blank forming a flaring bowl with radially extending 5 pockets pressed inward from the convex side game thereof, the end portions of said pockets being at an oblique angle to the surface of the bowl and their sides merging into said surface, said pockets forming projections from the concave side of said bowl, and pressing said bowl and thereby reversing the same with the projections extending from the convex side and with the ends of said pockets extending substantially parallel to the axis of the bowl.

4. In a method of forming pressed sheet metal spoked wheels, the steps of scallopingthe peripheral edge of a flat blank, and pressing'said blank forming a flaring bowl with pockets pressed inward from the flaring surface thereof, each pocket being in radial alignment with the projecting scallop and drawing the latter radially inward and forming thereof an end portion I of the pocket, the sides of said pocket merging, into the surface of the bowl.

5. In a method of forming pressed sheet metal spoked wheels, the steps of scalloping the peripheral edge .of' a fiat blank, pressing said blank forming a flaring bowl with pockets pressed inward from the convex side thereof, each pocket being in radial alignment with, the projecting scallop drawing the latter radially inward and forming thereof an end portion at an oblique angle to the surface of the bowl, the sides of said pocket merging into said surface, and re-- pressing said bowl thereby reversing the same and bringing the pr0jections formed by said pockets on to the convex side of the bowl with the ends of the pockets substantially parallel to the axis of the bowl.

JOHN MACLENNAN. 

